Method and apparatus for measuring the flow of fluids.



E. J. BERG.

METHOD AND APPARATUS FOR MEASURING THE FLOW 0F FLUIDS.

APPLICATION FILED APR. 22. 1914.

1,156,660. Patnted 001. 12, 1915.

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Hlmwmmn x auu gs Invehtor Ernst J. )3 kg,

Witnesses:

A; ZMZZLV 5 His fittorneg.

nmvsr J. BERG, OF

flow of fluids through conduits or passages,

UNIT-ED STATES; P E OFFICE.

scnEn o'rADY, NEW Yonx, ASSIGNOR 'ro GENERAL ELECTRIC ooMPANY,-ACQRPQRATION OF NEW YORK.

"METHOD ANnnrPABATUs non MEASUBIINGTTHE FLOW or FL IDS.

To all whom it may concern:

Be itknownthat I','ERNST J.' B ERG, a citizen of the United States,resldmg at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in Methods and Apparatusfor Measuring the Flow of Fluids, of which the following is aspecification.

This. invention relates to a novel and useful method of measuring ordetermining-the and to apparatus for applying or carrying out saidmethod.

temperature of the fluid to be measured, be

subjected to the action of the flowing fluid, the heat lost to the fluidby said body, or

the flow of heat between-the body and the fluid depends upon and ispractically proportional to the quantity. of fluid flowing, and theenergy supplied to the body to maintain it at the desired temperature,preferably a temperature of constant value, is a measure of the flow.

Some novel and useful forms of apparatus embodying the principle ofthe'method outlined above are illustrated in the accompanying drawingand described in subsequent portions of the specification. Forconvenience, the apparatus will be described as used for measuring theflow of steam through a main or pipe but its use is not limited to thatparticular fluid. It can be utilized to measure air, gas, etc., as willbe apparent to those skilled in the art. suitable heating means orradiator may be employed in the apparatus so long as its temperaturecondition can be' determined and the supply of energy required tomaintain it at the desired temperature can be measured with thenecessary degree of accuracy. An electrically heated means is preferablyused.

Referring to the drawing, Figure 1 is a H diagrammatic view of a meterand its con- Specification of Letters Patent.

' efficient.

Any

M Patented Oct. 12,1915. v I 'applicationfiled April 22, 1914."Seria1No. 833,804.

be metered flows can beiof any size required the conduit-is a radiatorin the form-of a conductor 5 made of some material that has a suitableresistance and that will not be corroded or attacked by the measuredfluid even when heated to relatively high temperature.

' This conductor is preferably madeof a material that also has a hightemperature co- It should be located at a point that is so far removedfrom obstructions and bends inthe oonduit as to be substantiallyunaffected by eddy currents set up bymember 7 oflarger size, and mountedin a plug 8 secured in the wall of the conduit opposite the plug 6. Theplug 8 has a chamber filled with insulatingpacking material 9, such forexample as asbestos or some other.

material that will not be affected by the fluid or the heat comingtherefrom. The packing 9 surrounds a portion of the member 7 andis heldin place by a threaded gland 10 and a washer 11. A bushing 12 insulatesthe conductor from the gland 10. Nuts 13 hold the end of the conductorin place and afford means for attaching or connecting it to anotherconductor. In Fig. 3, a modified form -of conductor is shown, thisconductor 14 being coiled about an insulating support 15 made of amaterial that is unaffected by the fluid or its temperature. Figs. 1 and2 is, however, simpler in its structure and has proved effective inservice. For these reasons it is usually to be preferred.

Referring to Fig. 1, the conductor 5 is, due to its resistance, heatedby the "current supplied from a battery 16, or other source of current.The degree to which the conductor is heated is such that its temperatureis higher than the temperature of the steam or fluid being measured, sothat it is cooled to a greater or less extent by the steam flow- Theconductor of v The meter will, of course, also measure superheatedsteam. When the temperature of the conductor changes, due to the coolingaction of the stream of steam, the resistance of the conductor varies.As heat is conveyed away from the conductor, the loss'is made good andthe conductor kept at a substantially constant temperature andresistance by supplying the necessary quantity of electrical energywhich is transformed into heat by the resistance of the conductor. Ifthe flow increases for a time, the supply ofenergy must be increased.When the flow decreases the conductor tends to rise in temperature andthe supply of energy must be decreased. The instrument or device 17,Fig. 1, enables the operator or observer to determine when and to whatextent the quantity of energy supplied to the conductor must be varied.This instrument has an indicator or pointer 18 that is moved by theresultant action of the torque due to two opposed coils which move in aconstant field set up by the permanent magnets 18*. The coil 19 isconnected to the terminals of the conductor '5 by suitable conductors 20and 21 and exert a torque proportional to the voltage impressed on theconductor. The torque on the pivot or shaft 22, due to the coil 19,

is opposed by the torque on the pivot exerted by the current flowingthrough the coil 23 which is in series with the conductor 5. When thetemperature of the conductor 5 is of the desired degree, the torquesexerted by the two coils 19 and 23 are equal and opposite and theindicator 18 stands in the position shown. The spring 24 tends to returnthe indicator to this position. If the temperature of the conductor 5varies, due to variations in the flow of steam, the efi'ects on thepointer or arm 18 of the torques due to the two coils, are no longerbalanced and the pointer moves from the position shown,

in one direction or the other, the direction depending upon whetherthe'temperature of the conductor is above or below normal. Theinstrument 17 thus acts as a temperaadjust the resistance 25 so as toincrease or decrease, as may be necessary, the current flowing throughthe conductor 5. The resistance is adjusted until the pointer returns tonormal position and the scale 26 can under certain conditions hegraduated in terms of the amount of resistance to be added to or takenout of the circuits, if desired.

It will be understood that the instrument 17 may take various forms, theessential feature of the same being that it shall indicate the ratiobetween two currents, one of which is proportional to the drop inpotential across the radiator 5, and the other of which is proportionalto the current flowing therethrough. In substance the instrument is. anohmmeter. It will be further understood that the precise form of thisinstrument forms no part of the present invention, such instrumentsbeing well known in the electrical measuring instrument art.

The quantity of steam passing through the main 4 varies and isproportional to the mean velocity of the stream of steam in the main,the velocity also varying at difi'erent points of the cross-section. Theconductor or radiator 5 extending as it does diametrically across saidcross-section, passes through these regions of difl erent velocities andthe heat conveyed away from it by the flowing steam depends upon thevelocity. Hence, the electric current which is supplied to heat theconductor 5 and maintain its temperature constant, is a measure of theheat carried away by the flowing steam, and, consequently, is a measureof the quantity of steam passing through the main in a given time.Obviously, the arrangement and structure of the conductor or radiatorcan be varied to meet the conditions found in conduits or passages whosecross-section is other than circular. The instrument or device 27 has acoil in circuit with the conductor 5 and the battery 16 that moves thepointer 28 a distance proportional to the current flowing in the circuitso that it shows on a suitably graduated scale 29 the rate offiow interms of pounds of steam per second or other appropriate units.

In Fig. 2, the temperature indicator 17 operates a switch or arm 30 inthe same manner that the pointer or arm 18, Fig. 1, is operated. The armstands between the contacts 31 and 32, as illustrated, when thetemperature of the conductor 5 is normal and it is moved into engagementwith one or the other of the contacts when the temperature varies aboveor below normal. Thus, it may serve in part as a visual indicator. en inengagement with one contact, the arm causes an excitation of the fieldof the electric motor 33 in such a way as to cause the motor to move thearm of the rheostat 34 to reduce the resistance in the circuit andthereby increase the heating current. When the switch is moved againstthe other contact, the field of the motor is so excited as to cause saidmotor to move the arm of the rheostat inthe opposite direction anddecrease the heating current. The current is thus automatically variedin such a manneras to keep the conductor 5 at a constant temperature andthis current which depends upon the quantity of steam flowing throughthe main, moves the arm 35 of the instrument or device 27". The movementof said arm causes a pen 36 carried by it to show can be calibrated interms of the flow per square inch if desired. Then the instrumentreadings must be multiplied by the ascer- Eained area of the conduit toobtain the total This meter, as Will be evident from the foregoing, doesnot require the introduction of any special fittings in the pipe line,nor does it objectionably obstruct the interior of the pipe. The holesfor the plugs 6 and 8 can be drilled and tapped in a short time. Themounting of the conductor 5 in the pipe is then a relatively simple andeasy operation. If it is not desired to keep the conductor in the pipefor continued observations, it is .readil removed and the openings inthe Wall 0 the pipe closed by. pipe plugs. The amount of energy used inthe meter is small, so small that it does not appreciably affect thetemperature of the flowing steam. Observations and tests also show thatthe meter is evidently independent of the static pressure of the steam,or at least that such a condition holds true over a wide range ofpressures.

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I nowconsider to represent the best embodiment thereof;but I desire to have it understood that the apparatus shown is onlyillustrative, and that the invention'can be carried out by other means.

What I claim as new and'desire to secure by Letters Patent of the UnitedStates, is

1. The method of measuring the flow of steam, air and other fluids,which comprises determining the amount of energy required to maintain ata constant temperature a body upon which said fluid exerts a coolingaction as it flows. 2. The method of measuring the flow of steam, airand other fluids, which comprises determining the amount of electricalenergy required to maintain at a constant temperature higher than thetemperature of the fluid, an electrical resistance means upon which theflowing stream of fluid exerts a cooling action dependent upon its rateof flow.

3. The method of measuring the flow of steam, air and other fluids,which comprises determining the amount of electrical energy required tomaintain at a constant temperature higher than the temperature of thefluid, an electrical resistance means immersed in the flowing stream offluid and exposed to the mean velocity thereof.

4. The method of determining the flow of steam, air andotherfluids,which comprises heating by an electric current to atemperature higher than the temperature of the fluid, a means arrangedin suchlrelationto the flowing fluid that its temperature is affected bythe fluid, and determiningthe flow by measuring the heating current.

5. The method of determining the flow of steam, air and other fluids,which comprises heating a suitable meansdoy an electric current, saidmeans being arranged in such re.- lation to the flowing fluid that atransfer of heat will take place between them, varying the heatingcurrent to maintain said means at a constant temperature, anddetermining the flow by measuring the heating current.

6. The method of measuring the flow of steam, air and other fluids,which comprises supplying energy to heat an electric resistance meansarranged in such relation to the flowing fluid that its temperature isaffected by the fluid to a degree dependent upon the rate of flow, theresistance of said means varying with its temperature, and varying thesupply of energy to maintain the resistance of said means constant.

7. The method of measuring the flow of steam, air and otherfiuids,-which comprises heating an electrical resistance device by anelectric current, said device being exposed to the mean velocity of theflowing stream of fluid so that a transfer of heat takes place betweenthe fluid and said device, the resistance of the device varying with itstemperature, varying the heating current to keep the resistance of thedevice constant, and determining the flow by measuring the heatingcurrent.

8. In an apparatus for measuring the flow of fluids, the. combination ofa radiator so arranged that its temperature is affected by the fluid, asource supplying energy to the radiator, means connecting the source andthe radiator, means for regulating the sup ply of energy to the radiatorto maintain it at a constant temperature, and a device controlled bysaid supply of energy that shows the flow of the fluid being measured.

9. In an apparatus for measuring the flow of fluids, the combination ofa radiator so arranged that its temperature is affected by the fluid, asource supplying energy to the I radiator, means connecting the sourceand the radiator, means for regulating the supply of energy to theradiator to maintain it at a temperaturehigher than the temperature ofthe fluid, and a device controlled by the energy supplied to theradiator and showing the rate of flow of the fluid being measured.

10. In a fluid meter. the combination of a conduit through which thefluid flows. a radiator arranged in the conduit so that its temperatureis affected by the flowing stream of fluid, a source supplying energy tothe radiator, means connecting the source and the radiator, means forregulating the supply of energy to the radiator to maintain it at aconstant temperature, and a device responsive to changes in the supplyof energy to the radiator that shows the rate of flow of the fluid beingmetered.

11. In a fluid meter, the combination of a conduit through which thefluid flows, a radiator arranged in the conduit and exposed to the meanvelocity of the fluid stream so that there is a transfer of heat betweenit and the flowing fluid, asource supplying energy to the radiator,means connecting the source and the radiator, means for regu lating thesupply of energy to the radiator to maintain it at a temperature higherthan the temperature of the fluid, and a device responsive to the supplyof energy to the radiator for showing the rate of flow of the fluidbeing metered.

12. In a fluid meter, the combination of an electrically heated radiatorso arranged that there is a transfer of heat between it and the flowingfluid, a source supplying current to the radiator, means connecting thesource and the radiator, means for regulating the supply of current tothe radiator to maintain it at a constant temperature, and a devicecontrolled by the heating current which shows the rate of flow of thefluid being metered.

13. Ina fluid meter, the combination of a, conduit through which thefluid flows, an electrical resistance device, whose resistance varieswith its temperature, that is so arranged that its temperature isaffected by the flowing fluid-to a degree dependent upon the rate offlow, a source supplying electrical energy to heat said device, meansconnecting the source and the device, means for varying the supply ofenergy to keep the resistance of the device constant, and meanscontrolled by the supply of energy to the dew ice foz showing the rateof flow.

14. In a fluid meter, the combination of a conduit through which thefluid flows, an

electric resistance device arranged in the conduit so that itstemperature is affected by the flowing fluid, a source supplying currentto heat said device, means connecting the source and the device, meansfor varying the current to maintain the device at a temperature higherthan the temperature of the fluid, and means responsive to the currentflowing in the circuit that shows the rate of flow of the fluid beingmetered.

15. In a fluid meter, the combination of a conduit through which thefluid flows, an

1 electric resistance device arranged in the conduit so that itstemperature is affected by the flowing fluid, a source supplying currentto heat the device, a variable resistance in circuit with sald sourceand devlce, means conduit so that there is a transfer of heat between itand the flowing fluid, a source supplying current to heat said device,means for showing the temperature condition of the device, a variableresistance in circuit with said source and device for varying thecurrent to maintain the device at a constant temperature, and meansresponsive to the current flowing in the circuit that shows the rate offlow of the fluid being measured.

17. In a fluid meter, the combination of a conduit through which thefluid flows, an electric resistance device arranged in the conduit sothat there is a transfer of heat between it and the flowing fluid, asource supplying current to heat the device, means that indicates thetemperature condition of the device, said means comprising a pivotedmember, an element that exerts a torque on said member in one directionthat is proportional to the current flowing through the device, andanother element that exerts a torque in the opposite direction that isproportional to the electromotive force impressed on the device, avariable resistance in circuit with said source and device forregulating the current to maintain the tem perature of the deviceconstant, and means controlled by the current flowing in the circuitthat shows the rate of flow of the fluid being measured.

18. In a fluid meter, the combination of a conduit through which thefluid'flows, an electrical resistance device so arranged that itstemperature is affected by the flowing fluid, a source supplying currentto heat the device, a variable resistance in circuit with said sourceand device, means responsive to the temperature condition of said devicefor regulating said resistance to vary the currentand therebymaintainthe device at a constant temperature, and means controlled by thecurrentflowing in the circuit that shows the rate of flow of the fluid'beingmeasured.

19. In a fluid meter, the combination of a conduit through which thefluid flows, an electric resistance device arranged in the conduit sothat there is a transfer of heat between it and the flowing fluid, asource supplying current to heat the device to a temperature higher thanthe temperature of the fluid, a connection between the source and theresistance device, a rheostat for regulating the current supplied to thedevice to maintain it at a constant temperature, a motor for operatingthe rheostat, means for controlling the motor that is responsive tochanges in the temperature condition of said device, and means actuatedby the heating current that shows the rate of flow of the fluid beingmeasured.

20. In a fluid meter, the combination of a conduit through which thefluid flows, an electric resistance device arranged diametrically acrossthe conduit, a source supplying current to heat the device to atemperature higher than the temperature of the fluid, an adjustableresistance in circuit with said source and device, means responsive tochanges in the temperature of said device for adjusting said resistanceto vary the current and thereby maintain the device at a constanttemperature, and means controlled I by the heating current that showsthe rate of flow of the fluid being measured.

21. In a fluid meter, the combination of a conduit through which thefluid flows, a heated wire arranged diametrically across the conduit andthe stream of fluid flowing therethrough, a source of electric energyconnected to the ends of the wire so that current will flow through thewire and heat it due to its resistance to a temperature higher than thetemperature of the fluid, an adjustable resistance in circuit with saidsource and wire, means responsive to changes in the temperature of thewire for adjusting said resistance to vary the current and therebymaintain the wire at a constant temperature and resistance, and meanscontrolled by the heating current that shows the rate of flow of thefluid being measured.

22. The method of measuring the flow of fluids, which comprisesdetermining the amount of energy required to maintain at constanttemperature, a body whose temflwralturecondition is affected by theflowing .In witness whereof, I have hereunto set my hand this 21st dayof April, 1914.

ERNST J. BERG.

Witnesses:

LYNDE D. HOKERK, BENJAMIN B. FULL.

